While it's the wrong forum etc. I'll help you out (saves everyone posting the "wrong forum" etc here). Save yoruself the bother and post in the right forums in future though, it really is easier (and you will find this info there too).
Quick brief 20 step response to flashing the MS25 going from my own flashing experience just a few days ago.
1. Download all necessary apps & fw from the usual places.
2. Run iPrep
3. Select the firmware (iXtreme the latest one for the samsung)
4. It'll ask if you want to use the found "quiet" firmware, if you do click ok, if youw ant the fast click no then wait for it to ask about fast and click yes.
5. Click list SCSI cards and select your Via
6. Choose the drive letter of the usb stick (which should have been inserted before step 1, if not put it in now)
7. Tick format/bootable
8. Click go for it
9. Shut down PC
10. connect the blaster to the internal SATA port of the card (aparently the external one doesnt like it - I'll be checking that later)
11.Set switches on blaster to the correct settings (depending on blaster or blaster ne, read the instructions for your settings, on team xecuters site)
12. Power up 360
13. Power up PC (assuming it will boot via USB and is set to do so)
14. Type (without quotes replacing x's for your serial no.) "iDump xxxxxxx xxxxx" and hit return
15. From the list choose XTREME (mine was number 2, yours probablywill be different)
16. wait for it to dump it all.
17. when all is done type "iFlash xxxxxxx xxxxx" and hit return
18. Wait for it to finish and it should ask about spoofing MS25 as it doesn't match, press Y
19. Wait for the PC to say it's done and to reboot.
20. Turn off the 360, reset the blaster to xbox mode and turn it back on... it should be done and should now boot your backups.
Some text, lables etc. may be slightly different, this is from memory and without the programs infront of me.
Hope that helps. Try the right forum if you need any more help.